It is well known that pneumatic steel-belted radial tires are widely used on automobiles, light trucks, and various other vehicles, trailers and machinery. Tires are often punctured by road debris during use. In some cases, the injury to the tire can be repaired and the tire can be put back into service, depending on the size and location of the puncture within the carcass of the tire. If the puncture is too large, or too close to the outer edge of the steel belt inside the tire, the tire should not be repaired, but instead should be scrapped.
The major tire manufacturers of the world have formed an industry trade group called the Rubber Manufacturers Association (“RMA”), through which they have collectively specified guidelines for the safe repair of tires. The RMA guidelines specify that certain punctures that fall between the outermost longitudinal tread grooves of a tire, such as 110 and 112 in FIG. 1, (the “traditional puncture repair area”) may be able to be repaired and the tire may be safely put back into service if proper repair procedures are followed. Punctures in the sidewall and adjacent shoulder area of a tire are considered unrepairable under the RMA standards.
If a puncture repair is performed too close to the edge of the steel belts in the tire, the tire may hold air pressure initially, but the damaged steel belt may fail to hold the tire together during the rigors of everyday use when a tire may be exposed to high speeds and extreme centrifugal forces. This may result in a catastrophic failure of the tire, commonly referred to as a blowout. Blowouts are to be avoided due to the possible dangerous consequences that might follow a blowout.
In tire stores across the globe the location of the puncture repair area causes disagreements between the owner of the punctured tire and the tire repair technician. The owners of punctured tires, not wanting to incur the expense of purchasing a new tire, will often request that a repair be attempted on punctures outside the traditional puncture repair area of the tire. Some tire repair technicians follow the guidelines for repair strictly. Some tire repair technicians bend the rules and attempt repairs slightly outside the traditional puncture repair area, guessing and hoping that the repair is not so close to the edge of the steel belt that the tire would fail during use. Others tire repair technicians don't follow the guidelines whatsoever, putting their clients in danger. They either don't care about the puncture repair area, or they don't know any better. Looking at a tire from a layman's perspective, there is no way to know the true boundaries of the puncture repair area of a tire so that it can be safely repaired.
The tire industry guidelines used to define the traditional puncture repair area are imprecise. The location of the outermost longitudinal tread grooves of different tires can vary widely based on the tread pattern of the tire, and may or may not correspond with the true puncture repair area which should be based on the location and engineering of the edge of the steel belts inside the tire. Technicians cannot tell exactly where the edge of the steel belts is located within the tire. Thus, the use of these outside longitudinal tread grooves was employed because it was the only visual markers that ensured that a service technician would not repair a tire with a puncture that was too close to the edge of the steel belts. There exists a need for a more precise manner of determining whether a puncture is located within the part of the tire carcass that can be safely repaired.
The present inventor recognized that a need exists for a repair boundary indicator to indicate which parts of the tire carcass can be safely repaired. The present inventor recognized (1) that any tires have a repairable area that extends beyond the traditional puncture repair area between the outermost longitudinal tread grooves; (2) that the current industry standard method of defining the puncture repair area is imprecise; (3) that many punctured tires are thrown away due to the use of the traditional puncture repair area which is an imprecise proxy for the true puncture repair area, imposing an unnecessary expense on vehicle owners; (4) that many tires with punctures outside the true puncture repair area are repaired and put back into service, putting the tire owner and the general public at risk; and (5) that there is a need for a repair boundary indicator that precisely delineates the exact location of the true puncture repair area and can be easily recognized by tire repair technicians and/or laymen worldwide.